WBE技术研究水线区破损涂层的剥离机制

Debonding Mechanism of Organic Coating with Man-made Defect in the Area nearby Water-line by WBE Technique

应用阵列电极(WBE)和电化学阻抗谱(EIS)技术,研究了破损涂层在3.5%(质量分数)Na Cl溶液中的电流分布及阻抗谱,并根据电流分布和涂层阻抗变化探究了破损涂层在水线区的剥离机制。结果表明:人为破损和涂层固有缺陷均对其附近涂层有加速阴极剥离的作用。浸泡初期,缺陷处涂层最先剥离,此后,涂层剥离主要在破损处和缺陷处附近优先发展。并且在水线作用下,缺陷处附近的涂层剥离向水线方向发展。水线上涂层较水线下剥离较晚,其剥离速率主要受水在涂层中的渗透速率控制。

The debonding process of organic coatings with desired artificial defects in 3.5%NaC1 solution was studied by means of wire beam electrode （WBE） method and electrochemical imped- ance spectroscopy （EIS） technique. The purpose was to reveal the relevant debonding mechanism of organic coatings in the area nearby water-line via analyzing the current distribution and the varia- tion of impedance spectroscopy during the experiment. It was found that, either the artificial defect or inherent defectcould accelerate cathodic debonding rate of the coating around the defects. Besides, due to the effect of waterline, a coating debonding, which initiated from one inherent defect will expand towards the waterline. The coating debonding occurred firstly on the area below the waterline, and then later above the waterline. The coating debonding rate on the area above waterline was controlled by the permeation rate of electrolyte through the coating,